1. Field of the Invention
The present invention relates to a camera apparatus that has a function to rotate a camera lens in a pan direction or a tilt direction and a method of controlling a camera apparatus.
2. Description of the Related Art
In the related art, in camera apparatuses such as a monitoring camera, it is generally accepted that a camera lens is rotated in a pan direction and a tilt direction for capturing images (for example, refer to JP-A-2012-103452).
As illustrated in FIG. 17, a dome-type camera 100 disclosed in JP-A-2012-103452 includes a hemispherical dome cover 101. Inside the dome cover 101, a lens unit 103 having a camera lens 102 is accommodated.
In the dome-type camera 100, there are provided a pan motor and a tilt motor. The lens unit 103 is rotatable in the pan direction and the tilt direction.
In this dome-type camera 100, in order to prevent vignetting from generating when capturing images in a direction at a wide tilt angle (direction close to horizontal direction), the lens unit 103 is offset from the center of the spherical dome cover 101 to an apex direction. If the lens unit 103 is offset from the center of the spherical dome cover 101, aberration occurs due to a lens effect of the dome cover 101. This aberration causes images to be projected in an overlapping manner, thereby being deteriorated in image quality as the photograph in FIG. 18B.
This phenomenon still occurs, even if the lens unit 103 is not offset, when a cylindrical portion is provided on an upper side of a hemispherical portion of the dome cover 101 as in FIG. 18A. This is because when the lens unit 103 is at an angle close to the horizontal level, penetration angle α1 of light L1 penetrating the dome cover 101 on an upper side of an optical axis CBM and penetration angle α2 of light L2 penetrating the dome cover 101 on a lower side thereof are different from each other, causing positions of focal points F1 and F2 to deviate from each other.
In order to improve this deterioration in the image quality, a partial shade filter 104 is included in the lens unit 103. An arc-shaped guide portion 105 is provided in an end portion of the partial shade filter 104 through a support piece 106. Two guide pins 107 are respectively provided on each of side surfaces of the guide portion 105 on the right and left. A pair of guide plates 108 are provided in an upper portion of the lens unit 103 on the right and left. The guide pin 107 of the guide portion 105 is inserted into an arc-shaped long hole 109 which is provided in the guide plate 108 in a slidable manner.
Accordingly, the partial shade filter 104 reciprocates between an insertion position and a retreat position and blocks one side of light incident on an image pickup device, and thus, it is possible to prevent the overlapping of the images.